1. Field of the Invention
The present invention relates to a label printing and applying device, principally of the portable type (hereinafter referred to as a "hand labeler"), and more particularly to a printing pressure damping mechanism for use with the hand labeler. The squeezing force applied to the hand lever is damped to a preset level to maintain the printing pressure exerted by the printing head at a constant predetermined level.
2. Description of the Prior Art
When the hand lever of a hand labeler is squeezed, the printing head is moved into abutment with the platen so that labels fed to the platen are printed with desired indicia. In a conventional hand labeler, the squeezing force applied to the hand lever determines the printing pressure of the printing head against the platen.
When the hand lever is squeezed with a strong force, the resulting strong printing pressure on the platen is not damped by the hand lever. When the type surface of the printing head is made of a rigid material, such as metal, the type surface is vibrated, at a small amplitude, to and from the platen by the strong printing pressure causing double printing of the labels. On the other hand, when the type surface of the printing head is made of an elastic material, such as rubber, the printing on the platen under elevated pressure crushes the types causing the imprints on the labels to become unclear.
Moreover, the rebound of the impact of the printing head hitting the platen is transmitted to the hand of the user directly through the hand lever. As a result, the user feels uncomfortable and the squeezing operation cannot be carried out smoothly.